Semiconductor device, semiconductor module and hard disk

ABSTRACT

A heat radiation electrode ( 15 ) is exposed from the back surface of an insulating resin ( 13 ), and a metal plate ( 23 ) is affixed to this heat radiation electrode ( 15 ). The back surface of this metal plate ( 23 ) and the back surface of a flexible sheet become substantially within a same plane, so that it is readily affixed to a second supporting member ( 24 ). In addition, the top surface of the heat radiation electrode ( 15 ) is made protrusive beyond the top surfaces of the pads ( 14 ) to reduce the distance between the semiconductor chip ( 16 ) and the heat radiation electrode ( 15 ). Accordingly, the heat generated by the semiconductor chip can be efficiently dissipated via the heat radiation electrode ( 15 ), the metal plate ( 23 ) and the second supporting member ( 24 ).

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a semiconductor device, asemiconductor module and a hard disk, and especially to a structurecapable of efficiently dissipating heat from a semiconductor chip.

[0002] Due to the recent growth of the use of semiconductor devices inportable devices and small/densely-mounted devices, the reduction insize and weight and the improvement in heat dissipation properties aredemanded at the same time. In addition, semiconductor devices aremounted on various types of substrates, which, in turn, are mounted invarious many systems as semiconductor modules. As for such a substrate,the use of a ceramic substrate, a printed board, a flexible sheet, ametal substrate or a glass substrate etc. may be contemplated, and thefollowing description gives one example thereof. Here, the semiconductormodule is explained as being mounted on a flexible sheet.

[0003]FIG. 17 shows an example in which a semiconductor module using aflexible sheet is mounted in a hard disk 100. This hard disk 100 may be,for example, the one described in detail in an article of NikkeiElectronics (No. 691, Jun. 16, 1997, p.92-).

[0004] This hard disk 100 is accommodated within a casing 101 made of ametal, and comprises a plurality of recording disks 102 that areintegrally attached to a spindle motor 103. Over the surfaces ofindividual recording disks 102, magnetic heads 104 are respectivelydisposed each with a very small clearance. These magnetic heads 104 areattached at the tips of suspensions 106 which are affixed to the ends ofrespective arms 105. A magnetic head 104, a suspension 106 and an arm105 together form one integral body and this integral body is attachedto an actuator 107.

[0005] the magnetic heads 104 must be electrically connected with aread/write amplifying IC 108 in order to perform read and writeoperations. Accordingly, a semiconductor module comprising thisread/write amplifying IC 108 mounted on a flexible sheet 109 is used,and the wirings provided on this flexible sheet 109 are electricallyconnected, ultimately, to the magnetic heads 104. This semiconductormodule 110 is called “flexible circuit assembly”, typically abbreviatedas “FCA”.

[0006] From the back surface of the casing 101, connectors 111 providedon the semiconductor module 110 are exposed, and these connector (maleor female) 111 and connectors (female or male) attached on a main board112 are engaged. On this main board 112, wirings are provided, anddriving ICs for the spindle motor 103, a buffer memory and other ICs fora driving, such as ASIC, are mounted.

[0007] The recording disk 102 spins at, for example, 4500 rpm via thespindle motor 103, and the actuator 107 detects the position of themagnetic head 104. Since this spinning mechanism is enclosed by a coverprovided over the casing 101, there is no way to completely prevent theaccumulation of heat, resulting in the temperature rise in theread/write amplifying IC 108. Therefore, the read/write amplifying IC108 is attached to the actuator 107 or the casing 101 etc. at a locationhaving a better heat conduction property than elsewhere. Further, sincerevolutions of the spindle motor 103 tend to high speed such as 5400,7200 and 10000 rpm, this heat dissipation has more importance.

[0008] In order to provide further detail of the FCA explained above,the structure thereof is shown in FIG. 18. FIG. 18A is the plan view,and FIG. 18B is a cross-sectional view taken along the line A-A whichcuts across the read/write amplifying IC 108 provided on one end of themodule. This FCA 110 is attached to an internal portion of the casing101 in a folded-state, so that it employs a first flexible sheet 109have a two-dimensional shape that can easily be folded.

[0009] On the left end of this FCA 110, the connectors 111 are attached,forming a first connection section 120. First wirings 121 electricallyconnected to these connectors 111 are adhered on the first flexiblesheet 109, and they extend all the way to the right end. The firstwirings 121 are then electrically connected to the read/write amplifyingIC 108. Leads 122 of the read/write amplifying IC 108 to be connected tothe magnetic heads 104 are connected with second wirings 123 which, inturn, are electrically connected to third wirings 126 on a secondflexible sheet 124 provided over the arm 105 and suspension 106. Thatis, the right end of the first flexible sheet 109 forms a secondconnection section 127 at which the first flexible sheet 109 isconnected to the second flexible sheet 124. Alternatively, the firstflexible sheet 109 and the second flexible sheet 124 may be integrallyformed. In this case, the second wirings 123 and the third wirings 126are provided integrally.

[0010] On the back surface of the first flexible sheet 109 on which theread/write amplifying IC 108 is to be provided, a supporting member 128is disposed. As for this supporting member 128, a ceramic substrate oran Al substrate may be used. The read/write amplifying IC 108 isthermally coupled with a metal that is exposed to inside of the casing101 through this supporting member 128, so that the heat generated inthe read/write amplifying IC 108 can be externally released.

[0011] With reference to FIG. 18B, a connecting structure between theread/write amplifying IC 108 and the first flexible sheet 109 will nowbe explained.

[0012] This flexible sheet 109 is constituted by laminating, from thebottom, a first polyimide sheet 130 (first PI sheet), a first adhesionlayer 131, a conductive pattern 132, a second adhesion layer 133 and asecond polyimide sheet 134 (second PI sheet), so that the conductivepattern 132 is sandwiched between the first and second PI sheets 130 and134.

[0013] In order to connect the read/write amplifying IC 108, a portionof the second PI sheet 134 and the second adhesion layer 133 areeliminated at the connection section to form an opening 135 whichexposes the conductive pattern 132. The read/write amplifying IC 108 iselectrically connected thereto through leads 122 as shown in the figure.

[0014] The semiconductor device packaged by an insulating resin 136 asshown in FIG. 18B has heat dissipating paths indicated by arrows forexternally dissipating its heat. Especially, since the insulating resin136 gives the thermal resistance, the semiconductor device has astructure that the heat generated by the read/write amplifying IC 108cannot be efficiently dissipated to the outside the device.

[0015] Further details will now be explained using this example in harddisk application. As for the read/write transfer rate of a hard disk, afrequency of 500 MHz to 1 GHz, or even a greater frequency, is required,so that the read/write speed of the read/write amplifying IC 108 must befast. To this end, the paths of the wirings on the flexible sheet thatare connected to the read/write amplifying IC 108 has to be shorten, andthe temperature rise in the read/write amplifying IC 108 must besuppressed.

[0016] Especially, since the recording disks 102 are spinning at a highspeed, and the casing 101 and the lid provide a molded space, theinterior temperature would rise up to around 70 to 80° C. On the otherhand, a typical allowable temperature for the operation of an IC isapproximately 125° C. This means that, from the interior temperature of80° C., a further temperature rise by approximately 45° C. ispermissible for the read/write amplifying IC 108. However, where thethermal resistance of the semiconductor device itself and FCA is large,this allowable operation temperature can easily be exceeded, therebydisabling the device to provide its actual performance level.Accordingly, a semiconductor device and FCA having superior heatdissipating properties are being demanded.

[0017] Furthermore, since the operation frequency is expected to furtherincrease in the future, further temperature rise is also expected in theread/write amplifying IC 108 itself due to the heat generated bycomputing operations. At room temperature, the IC can provide theperformance at its intended operation frequency, however, where it isplaced inside of a hard disk, its operation frequency has to be reducedin order to restrain the temperature rise.

[0018] As described above, further heat dissipating properties ofsemiconductor device, semiconductor module (FCA) are demanded inconnection with the increase of the operation frequency in the future.

[0019] On the other hand, the actuator 107, and the arms 105,suspensions 106 and magnetic heads 104 attached thereto has to bedesigned as light-weighted as possible in order to reduce the moment ofinertia. Especially, where the read/write amplifying IC 108 is mountedon the surface of the actuator 107 as shown in FIG. 17, the weightreduction is demanded also for the IC 108 and FCA 110.

SUMMARY OF THE INVENTION

[0020] The present invention was invented in consideration with theabove problems, and in the first aspect, it provides a semiconductordevice comprising a semiconductor chip integrally molded with aninsulating resin in a face-down state, the semiconductor device havingexposed on the back surface thereof a pad electrically connected to abonding electrode of the semiconductor chip and a heat radiationelectrode disposed over the surface of the semiconductor chip, whereinthe problem is solved by having the top surface of the heat radiationelectrode protrude beyond the top surface of the pad, and practicallydetermining the thickness of a connecting means for connecting thebonding electrode and the pad by the amount of this protrusion.

[0021] As for the means to connect the pad and the bonding electrode, anAu bump or a solder ball maybe used. The Au bump may comprise at leastone stage of an Au cluster, and the thickness thereof would be about 40μm for a one-stage bump and 70-80 μm for a two-stage bump. Since theheight of the heat radiation electrode surface generally matches withthe height of the pad surface, the space between the semiconductor chipand the heat radiation electrode is determined by the thickness of thebump. Accordingly, the space between the semiconductor chip and the heatradiation electrode cannot be made any smaller than the thickness of thebump. However, if the surface of the heat radiation electrode isdesigned to protrude beyond the surface of the pad by the substantialthickness of the bump, the space may be made smaller.

[0022] The thickness of a solder bump or a solder ball is approximately50 to 70 μm, and in this case also, the space may be made smallaccording to the same principle. A brazing material such as solder has agood wettability with the pad, so that when it is in a molten state, itspreads out over the surface of the pad, resulting in a smallerthickness. However, since the gap between the bonding electrode and thepad is determined by the amount of protrusion of the heat radiationelectrode, the thickness of the brazing material is determined by thisamount of the protrusion. Accordingly, by the amount the brazingmaterial can be made thicker, then the stress applied to the solder bumpmay be more distributed, so that the deterioration due to heat cyclescan be minimized.

[0023] In the second aspect, the problem is solved by using an Au bumpor a bump of a brazing material such as solder or a solder ball as theconnecting means.

[0024] In the third aspect, the problem is solved by providing a metalplate on the exposed portion of the heat radiation electrode in a mannerso that it protrudes beyond the back surface of the pad.

[0025] This protrusive metal plate and the back surface of a flexiblesheet which serves as a first supporting member may be made within asame plane, so that a structure is provided, in which the metal platecan be adhered or abutted to the interior of a casing, especially to amember of the casing having a flat surface such as a heat sink plateetc.

[0026] In the fourth aspect, the problem is solved by disposing the backsurface of the pad and the back surface of the heat radiation electrodesubstantially within a same plane.

[0027] In the fifth aspect, the problem is solved by affixing thesemiconductor chip and the heat radiation electrode together by aninsulating material.

[0028] In the sixth aspect, the problem is solved by affixing the heatradiation electrode and the metal plate together by an insulatingmaterial or a conductive material.

[0029] In the seventh aspect, the problem is solved by integrallyforming the heat radiation electrode and the metal plate from a samematerial.

[0030] In the eighth aspect, the problem is solved by having the backsurface of the insulating resin protrude beyond the back surface of thepad.

[0031] When forming a brazing material such as solder over the backsurface of the pad, the thickness of the solder may be determined by theamount of this protrusion. It also prevents short-circuiting with theconductive pattern extending over the back surface of the semiconductordevice.

[0032] In the ninth aspect, the problem is solved by having the sidesurfaces of the pad and the back surface of the insulating resin thatextends from the side surfaces of the pad define a same curved surface.

[0033] The insulating resin exposed from the back surface of thesemiconductor device would define a curved surface when etched, andwould exhibit a shape which provides a point contact rather than a facecontact. Accordingly, the frictional resistance of the back surface ofthe semiconductor device is reduced, thereby facilitatingself-alignment. It also provides a relief for the brazing material whichis more effective comparing to a structure in which the protrusivefeature of the back surface of the insulating resin is flat. In this waythe short-circuiting between the adjacent bumps of the brazing materialmay be avoided.

[0034] In the tenth aspect, a semiconductor module is provided, whichcomprises a first supporting member having a conductive pattern providedthereon and a semiconductor device comprising a semiconductor chip whichis electrically connected to the conductive pattern and is integrallymolded by an insulating resin in a face-down state, the semiconductordevice having exposed on the back surface thereof, a pad electricallyconnected to a bonding electrode of the semiconductor chip and a heatradiation electrode disposed over the surface of the semiconductor chip,wherein the problem is solved by having the top surface of the heatradiation electrode protrude beyond the top surface of the pad, anddetermining the thickness of a connecting means for connecting thebonding electrode and the pad according to the amount of thisprotrusion, an by electrically connecting the pad to the conductivepattern provided on the first supporting member, and providing anopening to the first supporting member at a location which correspondsto the heat radiation electrode, the opening accommodating a metal platewhich is affixed to the heat radiation electrode.

[0035] The distance between the semiconductor chip and the heatradiation electrode can be set so as to assure the conduction of heat,and at the same time, the metal plate thermally coupled with the heatradiation electrode can be abutted to a heat-dissipating substrateprovided under the first supporting member.

[0036] In the eleventh aspect, the problem is solved by adhering asecond supporting member having the metal plate affixed thereto to theback surface of the first supporting member, and affixing this metalplate and the heat radiation electrode together.

[0037] In the twelfth aspect, the problem is solved by forming the heatradiation electrode and the metal plate integrally from a same material.

[0038] As shown in FIGS. 13 and 14, the metal plate and the heatradiation electrode may be formed integrally by etching a conductivefoil, thereby unnecessitating the step for affixing the metal plate.

[0039] In the thirteenth aspect, the problem is solved by providing afixation plate made of a conductive material over the second supportingmember at a location which corresponds to the metal plate, and bythermally coupling the fixation plate and the metal plate.

[0040] In the fourteenth aspect, the problem is solved by forming,respectively, the metal plate mainly by Cu, the second supporting membermainly by Al, and the fixation plate by a plated film mainly made of Cuformed on the second supporting member.

[0041] In this way, the thermal resistance between the second supportingmember and the fixation plate may substantially be reduced, so that thetemperature rise in the semiconductor chip may be effectively prevented.

[0042] In the fifteenth aspect, the problem is solved by having the backsurface of the insulating resin protrude beyond the back surface of thepad.

[0043] In the sixteenth aspect, the problem is solved by having the sidesurfaces of the pad and the back surface of the insulating resin whichextends from the side surfaces of the pad define the same curvedsurface.

[0044] In the seventeenth aspect, the problem is solved by using thesemiconductor chip as a read/write amplifying IC for a hard disk.

[0045] In the eighteenth aspect, a semiconductor device is provided,which comprises a semiconductor chip integrally molded by an insulatingresin in a face-down state, the semiconductor device having exposed onthe back surface thereof, a pad electrically connected to a bondingelectrode of the semiconductor chip, an external electrode extending viaa wiring integral with the pad, and a heat radiation electrode disposedon the surface of the semiconductor chip, wherein the problem is solvedby having the top surface of the heat radiation electrode protrudebeyond the top surface of the pad, and determining the thickness of aconnecting means for connecting the bonding electrode and the padpractically by the amount of this protrusion.

[0046] In the nineteenth aspect, the problem is solved by using an Aubump or a bump made of a brazing material such as solder, or a solderball.

[0047] In the twentieth aspect, the problem is solved by disposing ametal plate over the exposed portion of the heat radiation electrode ina manner so that it protrudes beyond the back surface of the externalconnection electrode.

[0048] In the twenty-first aspect, the problem is solved by disposingthe back surface of the external connection electrode and the backsurface of the heat radiation electrode substantially within a sameplane.

[0049] In the twenty-second aspect, the problem is solved by affixingthe heat radiation electrode and the metal plate together by aninsulating material.

[0050] In the twenty-third aspect, the problem is solved by affixing theheat radiation electrode and the metal plate together by an insulatingmaterial or a conductive material.

[0051] In the twenty-fourth aspect, the problem is solved by integrallyforming the heat radiation electrode and the metal plate from a samematerial.

[0052] In the twenty-fifth aspect, the problem is solved by having theback surface of the insulating resin protrude beyond the back surface ofthe external connection electrode.

[0053] In the twenty-sixth aspect, the problem is solved by having theside surfaces of the external connection electrode and the back surfaceof the insulating material which extends from the side surfaces of theexternal connection electrode define a same curved surface.

[0054] In the twenty-seventh aspect, a semiconductor module is provided,which comprises a first supporting member having a conductive patternprovided thereon, and a semiconductor device including a semiconductorchip which is electrically connected to the conductive pattern and isintegrally molded by an insulating resin in a face-down state, thesemiconductor device having exposed on the back surface thereof, a padelectrically connected to a bonding electrode of the semiconductor chip,an external connection electrode provided via a wiring integral with thepad and a heat radiation electrode disposed over the surface of thesemiconductor chip, wherein the problem is solved by having the topsurface of the heat radiation electrode protrude beyond the top surfaceof the pad, and determining the thickness of a connecting means forconnecting the bonding electrode and the pad practically by the amountof this protrusion, and by electrically connecting the conductivepattern provided on the first supporting member and the externalconnection electrode, and providing an opening in the first supportingmember at a location corresponding to the heat radiation electrode, theopening accommodating a metal plate affixed to the heat radiationelectrode.

[0055] In the twenty-eighth aspect, the problem is solved by adhering asecond supporting member having the metal plate affixed thereto onto theback surface of the first supporting member.

[0056] In the twenty-ninth aspect, the problem is solved by integrallyforming the heat radiation electrode and the metal plate from a samematerial.

[0057] In the thirtieth aspect, the problem is solved by providing afixation plate made of a conductive material on the second supportingmember at a location corresponding to the metal plate, and by thermallycoupling the fixation plate and the metal plate.

[0058] In the thirty-first aspect, the problem is solved by forming,respectively, the metal plate mainly by Cu, the second supporting membermainly by Al and the fixation plate by a plated film mainly made of Cuformed on the second supporting member.

[0059] In the thirty-second aspect, the problem is solved by having theback surface of the insulating adhesive means protrude beyond the backsurface of the external connection electrode.

[0060] In the thirty-third aspect, the problem is solved by having theside surfaces of the external connection electrode and the insulatingadhesive means extending from the side surfaces of the externalconnection electrode define a same curved surface.

[0061] In the thirty-fourth aspect, the problem is solved by using thesemiconductor chip as a read/write amplifying IC for a hard disk.

BRIEF DESCRIPTION OF THE DRAWINGS

[0062]FIG. 1 is a diagram illustrating a semiconductor module accordingto the present invention.

[0063]FIG. 2 is a diagram illustrating a semiconductor device accordingto the present invention.

[0064]FIG. 3 is a diagram illustrating a semiconductor device accordingto the present invention.

[0065]FIG. 4 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

[0066]FIG. 5 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

[0067]FIG. 6 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

[0068]FIG. 7 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

[0069]FIG. 8 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

[0070]FIG. 9 is a diagram illustrating a semiconductor device of thepresent invention.

[0071]FIG. 10 is a diagram illustrating a film for preventing therunning of a material, which is formed on the conductive pattern.

[0072]FIG. 11 is a diagram illustrating a semiconductor module of thepresent invention.

[0073]FIG. 12 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

[0074]FIG. 13 is a diagram illustrating a manufacturing step of thesemiconductor device according to the present invention.

[0075]FIG. 14 is a diagram illustrating a manufacturing step of thesemiconductor device according to the present invention.

[0076]FIG. 15 is a diagram illustrating a semiconductor device accordingto the present invention.

[0077]FIG. 16 shows a series of diagrams illustrating several methodsfor forming a connection structure of the semiconductor chip and thepads.

[0078]FIG. 17 is a diagram illustrating a hard disk.

[0079]FIG. 18 is a diagram illustrating a conventional art semiconductormodule used in the hard disk of FIG. 17.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0080] The present invention provides a thin and small semiconductordevice having a superior heat-dissipating capability, and asemiconductor module having this semiconductor device mounted thereon,such as a semiconductor module attached on a flexible sheet (hereinafterreferred to as “FCA”), thereby providing improvement in thecharacteristics of, for example, a hard disk.

[0081] First, reference shall be made to FIG. 17 illustrating anexemplary hard disk in which such an FCA is implemented, and then toFIG. 1 showing the FCA. A semiconductor device mounted on this FCA andthe manufacturing method thereof are shown in FIGS. 2 through 16.

[0082] (Embodiment 1)

[0083] The first embodiment is provided to illustrate an apparatus inwhich the FCA is implemented. As for this apparatus, the exemplary harddisk 100 shown in FIG. 17 that has been used for illustrating theconventional art will again be used.

[0084] The hard disk 100 may be mounted on a main board 112 as necessaryin order to place it in a computer etc. This main board 112 includesfemale (or male) connectors. Male (or female) connectors 111 provided onthe FCA and exposed from the back surface of the casing 101 areconnected with these connectors on the main board 112. Within the casing101, a plurality of recording disks 102 used as a recording medium areprovided in a number corresponding to the storage capacity of the harddisk. Since each of the magnetic heads 104 floats and scans over each ofthe recording disks 102 at a position approximately 20 nm to 30 nm awayfrom the disk, the interval between the recording disks 102 are designedso as to allow this scanning to be undisturbed. The disks are attachedto a spindle motor 103 at this interval. This spindle motor 103 ismounted on a mounting board, and a connector arranged on the backsurface of this mounting board is exposed from the back surface of thecasing 101. This connector is connected to a connector of the mainboard. Accordingly, mounted on this main board 112 are, an IC fordriving the read/write amplifying IC 108 for the magnetic heads 104, anIC for driving the spindle motor 103, an IC for driving an actuator, abuffer memory for temporarily storing data, and other ASICs etc. forimplementing the manufacturer's own driving scheme. Of cause, anyadditional active and passive elements may also be mounted.

[0085] The wirings connecting between the magnetic heads 104 and theread/write amplifying IC 108 are designed to be as short as possible, sothat the read/write amplifying IC 108 is disposed over the actuator 107.However, since the semiconductor device hereinafter explained isextremely thin and light-weighted, it may be mounted over the arm 105 orthe suspension 106 instead of the actuator. In this case, as shown inFIG. 1B, the back surface of the semiconductor device 10 exposes fromthe opening 12 of the first supporting member 11, and the back surfaceof the semiconductor device 10 is thermally coupled with the arm 105 orthe suspension 106, so that the heat from the semiconductor device 10 isexternally dissipated via the arm 105 and the casing 101.

[0086] Where the read/write amplifying IC 108 is mounted on the actuator107 as shown in FIG. 17, the circuits for reading and writing respectivechannels are formed on a single chip so as to allow the plurality ofmagnetic sensors to read and write. However, a dedicated read/writecircuit may be mounted on each of the suspensions 106 for each of themagnetic heads 104 that are attached to the respective suspension 106.In this way, the wiring distance between a magnetic head 104 and aread/write amplifying IC 108 may be far shorter than that of thestructure shown in FIG. 18, and such a short distance would reduce theimpedance, resulting in an improved read/write rate. Since in thisexample, an application to a hard disk is assumed, a flexible sheet hasbeen selected for the use as the first supporting member, however,depending on the types of the apparatus, a printed board, a ceramicsubstrate or a glass substrate may instead be selected as the firstsupporting member.

[0087] (Embodiment 2)

[0088] The semiconductor device according to the second embodiment ofthe present invention will now be explained with reference to FIG. 2.FIG. 2A is a plan view of the semiconductor device, and FIG. 2B is across-sectional view taken along the ling A-A. FIG. 2C is a diagram forillustrating the reason for providing the protrusive heat radiationelectrode 15.

[0089] In FIG. 2, the following elements are shown as embedded within aninsulating resin 13; pads 14, a heat radiation electrode 15 providedwithin a region surrounded by these bonding pads 14, and a semiconductorchip 16 disposed over the heat radiation electrode 15. The semiconductorchip 16 is mounted in a face-down state, and using an insulatingadhesive means 17 it is affixed to the heat radiation electrode 15 whichis divided into four pieces in order to achieve good adhesion. Theisolation trenches formed by this division are indicated by the numeral18A. Where the gap between the semiconductor chip 16 and the heatradiation electrode 15 is so small that the intrusion of the insulatingadhesive means 17 is disturbed, then trenches 18B that are shallowerthan the aforementioned isolation trenches 18A may be formed on thesurface of the heat radiation electrode 15.

[0090] The bonding electrodes 19 of the semiconductor chip 16 and thepads 14 are electrically connected via connections 20 made of a brazingmaterial such as solder. Alternatively, stud bumps of Au may also beused in the place of solder.

[0091] There are other types of connecting methods for achieving theseconnections. For example, after bumps are provided on the respectivebonding electrodes 19 of the semiconductor chip, the connections may beobtained through the application of ultrasonic wave to these bumps orthrough pressure welding. Also, at the peripheries of thepressure-welded bumps, solder, a conductive paste or anisotropicconductive particles may be provided. The greater details of thesestructures will be provided at the end of this embodiment section.

[0092] The back surfaces of the pads 14 are exposed from the insulatingresin 13, and as they are, form external connection electrodes 21, andthe side surfaces of the pads 14 are etched non-anisotropically. Theseetched portions are formed by a wet etching method, so that they have acurved structure which promotes an anchor effect.

[0093] The present structure is constituted by five elements includingthe semiconductor chip 16, a plurality of conductive patterns 14, theheat radiation electrode 15, the insulating adhesive means 17, and theinsulating resin 13 within which all the former elements are embedded.Within a region for disposing the semiconductor chip 16, the insulatingadhesive means 17 is formed over and between the pieces of the heatradiation electrode 15, especially within the isolation trenches 18formed by etching, so that the back surface of the insulating adhesivemeans is exposed from the back surface of the semiconductor device 10A.All the elements including the above are molded within the insulatingresin 13. The pads 14, heat radiation electrode 15 and semiconductorchip 16 are supported by the insulating resin 13 and the insulatingadhesive means 17.

[0094] As for the insulating adhesive means 17, an adhesive made of aninsulating material or an under fill material is preferable. Where anadhesive is employed, it may be applied to the surface of thesemiconductor chip 16 in advance, and cured as the pads 14 are connectedusing Au bumps instead of solder 20. In the case of an under fillmaterial 17, it may be injected into the gap after the solder 20 (orbumps) and pads 14 are connected.

[0095] As for the insulating resin, a heat-curable resin such as epoxyresin, or a thermoplastic resin such as polyimide resin or polyphenylenesulfide etc. may be used.

[0096] Any resin material can be used as the insulating resin 13 as longas it can be cured using a metal mold, or can be applied by dipping orcoating. For the conductive pattern 14, a conductive foil mainly made ofCu, a conductive foil mainly made of Al or an Fe—Ni alloy, a laminate ofAl—Cu, Al—Cu—Al or Cu—Al—Cu, or the like maybe used. Of course any otherconductive material may also be used, and especially desirable are thoseconductive materials that can be etched, or that can be evaporated bylaser. Where the half-etching, plating and thermal stresscharacteristics are concerned, a conductive material mainly made of Cuformed through rolling is suitable.

[0097] According to the present invention, the trenches 18 and 22 arealso filled with the insulating resin 13 and the insulating adhesivemeans 17 so that slipping-out of the conductive pattern may beprevented. Also, by performing non-anisotropic etching through adry-etch or wet-etch method, the side surfaces of the bonding pads 14may be processed to have a curved structure thereby promoting the anchoreffect. This realizes a structure that would not allow the conductivepattern 14 and heat radiation electrode 15 to slip out from theinsulating resin 13.

[0098] Moreover, the back surface of the heat radiation electrode 15 isexposed from the back surface of the package. Therefore, the backsurface of the heat radiation electrode 15 would form a structure thatcan be abutted or attached to the later-described metal plate 23, thesecond supporting member 24 or a fixation plate 25 formed on the secondsupporting member 24. Accordingly, this structure allows the heatgenerated by the semiconductor chip 16 to be dissipated into the secondsupporting member 24, thereby preventing the temperature rise in thesemiconductor chip 16 so that the driving current and driving frequencyof the semiconductor chip 16 may be increased.

[0099] In the semiconductor device 10A, since the pads 14 and the heatradiation electrode 15 are supported by the insulating resin 13, whichis a mold resin, the use of any supporting substrate is unnecessitated.This structure is one feature of the present invention. The conductivepaths of the conventional art semiconductor device are supported by asupporting substrate (flexible sheet, printed board or ceramicsubstrate), or by a lead frame, and this means that the conventional artdevice includes those elements that could potentially be unnecessitated.On the other hand, the device of the present invention is constituted byonly essential, minimal elements, and it eliminates the need for asupporting substrate, thus it can be made thin and light-weighted, andat the same time, its cost may be reduced as it require less materialcost. Accordingly, as explained in the description of the firstembodiment, it may be mounted on the arms or suspensions of a hard disk.

[0100] From the back surface of the package, the pads 14 and the heatradiation electrode 15 are exposed. Where a brazing material such assolder is applied over these regions, since the area of the heatradiation electrode 15 is larger, the thickness of the applied brazingmaterial becomes uneven. Accordingly, in order to make the filmthickness of the brazing material even, an insulating film 26 is formedon the back surface of the semiconductor device 10A. The regionssurrounded by dotted lines 27 shown in FIG. 2A indicate the portions ofthe heat radiation electrode 15 exposed from the insulating film 26, andthese portions are exposed in the same manner as the exposedsquare-shaped portions of the back surfaces of the bonding pads 14, theindividual potions of the heat radiation electrode 15 exposed from theinsulating film 26 and the exposed portions of the bonding pads 14 havethe same size.

[0101] Thus, the sizes of the portions wettable by the brazing materialare substantially identical so that the brazing material formed theretowould have substantially the same thickness. This would not change evenafter a solder print or reflow process. The same is true for aconductive paste of i.e. Ag, Au or Ag—Pd etc. Given this structure, moreaccurate calculation can be performed to determine how much the backsurface of the metal plate 23 should protrude beyond the back surfacesof the pads 14.

[0102] When the metal plate 23 and the conductive pattern 32 aredesigned to align within a same plane, then both the pads 14 and theheat radiation electrode 15 may be soldered at once.

[0103] The exposed portions 27 of the heat radiation electrode 15 may beformed to have a larger size than that of the exposed portions of thebonding pad in consideration with the capability to dissipate the heatfrom the semiconductor chip.

[0104] The provision of the insulating film 26 also allows theconductive pattern 32 provided on the first supporting member 11 to bedisposed over the back surface of the semiconductor device. Generally,the conductive pattern 32 provided on the first supporting member 11 isso arranged that it bypasses the region over which the semiconductordevice is attached in order to prevent short circuiting, however, theprovision of the insulating film 26 allows it to be disposed withoutsuch bypassing. In addition, the insulating resin 13 and the insulatingadhesive means 17 protrude beyond the conductive patterns, therebyenabling to prevent short-circuiting between solder balls SD provided onthe back surface of the semiconductor device 10A.

[0105] Furthermore, the present invention is characterized in that thetop surface of the heat radiation electrode 15 is made protrusive beyondthe top surfaces of the pads 14.

[0106] As for a means to connect the pads 14 and the bonding electrodes19, the use of Au bumps or solder balls may be contemplated. An Au bumpmay comprise at least one stage of an Au cluster, and the thicknessthereof would be about 40 μm for a one-stage bump and 70-80 μm for atwo-stage bump. Since the height of the heat radiation electrode 15surface is generally designed to match with the height of the pads 14 asshown in FIG. 2C, the distance “d” between the semiconductor chip 16 andthe heat radiation electrode 15 is practically determined by thethickness of the bumps. Accordingly, the above space cannot be made anysmaller than the thickness of the bumps in the case of FIG. 2C, so thatit is not possible to reduce the heat resistance given by this distance.However, as shown in FIG. 2, if the surface of the heat radiationelectrode is made protrusive beyond the surface of the pads by athickness substantially equal to the thickness of the bumps, thisdistance “d” may be made smaller, so that the heat resistance betweenthe semiconductor chip 16 and the heat radiation electrode 15 may bereduced.

[0107] The thickness of the solder bumps or solder balls isapproximately 50 to 70 μm, and in this case also, the distance “d” maybe made smaller based on the same principle. A brazing material such assolder has a good wettability with the pads, so that when it is in amolten state, it spreads out over the entire surfaces of the pads,resulting in a smaller thickness. Further, since the gap between thebonding electrodes 19 and the respective pads 14 is determined by theamount of protrusion of the heat radiation electrode 15, the thicknessof the brazing material is determined by this amount of the protrusionso that the aforementioned running of solder may also be prevented.Accordingly, by the amount the brazing material can be made thicker, thestress applied to the solder may be more distributed, so that thedeterioration due to heat cycles can be minimized. In addition, byadjusting this amount of protrusion, a cleaning fluid may be introducedinto this gap.

[0108] This protrusive structure of the heat radiation electrode 15 isapplicable to all of the embodiments of the present inventionhereinafter explained.

[0109] (Embodiment 3)

[0110]FIG. 3 shows another semiconductor device 10B according to thepresent invention. FIG. 3A is a plan view thereof, and FIG. 3B is across-sectional view taken along the line A-A. Since this structure issimilar to that of FIG. 2, the following provides only the descriptionpertinent to those features that are different from the device in FIG.2.

[0111] In FIG. 2, the back surfaces of the pads 14 are used as theexternal connection electrodes as they are, however, in this embodiment,an integral wiring 30 and an external connection electrode 31 integrallyformed with the wiring 30 are provided to each of the pads 14.

[0112] The rectangle shown by a dotted line represents the semiconductorchip 16, and on the back surface of the semiconductor chip 16, theexternal connection electrodes 31 are disposed in a ring-likearrangement as shown. This arrangement is identical or similar to thatof a known BGA. In order to alleviate the distortion at the connectionpoints, they may be formed in a wavy shape.

[0113] When the semiconductor chip 16 is disposed directly over theconductive patterns 14, 30 and 31 and the heat radiation electrode 15,the patterns and the heat radiation electrodes are short-circuited viathe back surface of the semiconductor chip 16. Accordingly, the adhesivemeans 17 has to be an insulating material, and any conductive materialmust not be used.

[0114] The conductive pattern 32 on the first supporting member 1 shownin FIG. 1 is connected to the external connection electrodes 31, and theback surfaces of the pads 14 and the wirings 30 are covered by theinsulating film 26. The dotted circles indicated in the regions of theexternal connection electrodes 31 and the heat radiation electrode 15represent the portions that expose from the insulating film 26.

[0115] Furthermore, since the external connection electrodes 31 areprovided over the back surface of the semiconductor chip 16, the heatradiation electrode 15 is designed to be smaller than the heat radiationelectrode 15 of FIG. 2. Accordingly, the insulating adhesive means 17covers the heat radiation electrode 15, external connection electrodes31 and the wirings 30. The insulating resin 13 would then form anintegral body with the insulating adhesive means 17, thus, would coverthe pads 14, the wirings 30, the semiconductor chip 16 and the solder(or bump) 20.

[0116] The present embodiment has an advantage in that, even when thenumber of the bonding pads 14 is extremely large and their size has tobe reduced, the size of the external connection electrodes 31 may bemade sufficiently large by connecting them via the wirings andrearranging them as the external connection electrodes. Also, theprovision of the wirings alleviates the distortion stress applied to thebonding sections. Especially, wavy wirings are effective. The presentinvention also provides a feature that allows the space for thethickness of the solder to be reserved by having the surface of the heatradiation electrode protrude. Accordingly, with the provision of thewirings and the design allowing the solder sections to have increasedthickness, the reliability of the connections between the semiconductorchip 16 and the pads 14 may be improved.

[0117] Since the semiconductor chip 16 and the heat radiation electrode15 are affixed together by an insulating adhesive means 17, which is aninsulating material, there is a concern of thermal resistance. However,by constituting the insulating adhesive means by a silicon resin mixedwith fillers such as those made of silicon oxide or aluminum oxide thatcontribute to thermal conduction, the heat from the semiconductor chip16 may efficiently be conducted into the heat radiation electrode 15.

[0118] The distance between the heat radiation electrode 15 and thesemiconductor chip 16 may be made even by designing the fillers to havea same diameter. Therefore, where a very small separation is desired inconsideration with the thermal conduction, such a small separation mayeasily be formed by lightly applying a pressure to the semiconductorchip 16 while the insulating adhesive means is in a soft state. Since,in this embodiment, the use of aluminum oxide fillers having a diameterof 10 μm is assumed, the distance between the semiconductor chip 16 andthe heat radiation electrode 15 is retained substantially at 10 μm.

[0119] (Embodiment 4)

[0120] The fourth embodiment explains a manufacturing method of thesemiconductor devices 10A and 10B. Between the manufacturing methods ofthe semiconductor devices 10A and 10B, the only difference is whether itfabricates the pattern of FIG. 2 which includes only the heat radiationelectrode 15 and the pads 14, or the pattern of FIG. 3 whichadditionally includes the wirings 30 and the external connectionelectrodes 31, and the rest of the manufacturing steps are substantiallyidentical. Since either of the methods employs half-etching to formconvex patterns, the explanation will be provided herein with referenceto the manufacturing method of the semiconductor device 10B shown inFIG. 3. FIGS. 4 through 9 provide the cross-sectional views of FIG. 3Ataken along the line A-A.

[0121] First, as shown in FIG. 4, a conductive foil is provided. Thethickness of the foil is desirably between 10 μm and 300 μm, and herein,a rolled copper foil in a thickness of 70 μm is used. Next, over thesurface of this conductive foil 40, a conductive film 41 or a photoresist is formed as an etching mask. This pattern is identical to thepattern of the heat radiation electrode 15 of FIG. 3A.

[0122] Thereafter, the conductive foil 40 is half-etched via theconductive film 41 or the photo resist. The depth of etching should beshallower than the thickness of the conductive foil 40, andapproximately equal to the substantial thickness of the solder 20 (orbumps).

[0123] By this half-etching, a convex pattern of the heat radiationelectrode 15 manifests on the surface of the conductive foil 40. (FIG.4)

[0124] Next, an etching mask PR is formed over the areas correspondingto the patterns of the pads 14, the wirings 30, the external connectionelectrode 31 and the heat radiation electrode 15, and again, the foil ishalf-etched. There are two types of formation methods for forming theportion of the etching mask corresponding to the region of the heatradiation electrode 15, one for forming PR1 and another for forming PR2,and depending on the method selected, the resultant geometry of the sidesurfaces of the heat radiation electrode slightly differs. Where amaterial having a slow etching rate such as Ni is selected as theconductive film, an overhang is formed, thus, the anchor effect can beexpected.

[0125] At the layer below the etching mask, a conductive film made ofAu, Ag, Pd or Ni etc. is formed over at least the locationscorresponding to the pads. This film is formed in order to allowbonding.

[0126] The conductive foil 40 is then half-etched using the etching maskPR. The depth of this etching is arbitrary as long as it is shallowerthan the remaining thickness of the conductive foil 40. A shalloweretching depth allows the formation of a finer pattern.

[0127] By this half-etching, the convex patterns of the pads 14, thewirings 30 and the external connection electrodes 31 manifest, and theheat radiation electrode 15 that has been half-etched in the previousstep manifests as being protrusive beyond the pads 14, the wiring 30 andthe external connection electrodes 31. (FIG. 5)

[0128] The conductive foil 40 used herein is a Cu foil mainly made ofCu, which has been formed by rolling. This is because a rolled Cu foilis superior in flexibility. However, it may also be a conductive foilmade of Al or an Fe—Ni alloy, or a laminate of Cu—Al, Al—Cu—Al orCu—Al—Cu. The laminate of Al—Cu—Al or Cu—Al—Cu, especially, can preventwarping caused by a difference in thermal expansion coefficients.

[0129] The insulating adhesive means 17 is then applied onto the regioncorresponding to the rectangle indicated by a dotted line in FIG. 3.This insulating adhesive means 17 is provided in and over the isolationtrench 22 between the heat radiation electrode 15 and the externalconnection electrodes 31, an isolation trench between the heat radiationelectrode 15 and the wirings 30, and isolation trenches between wirings30.

[0130] The semiconductor chip 16 is then affixed to the region on whichthe insulating adhesive means 17 has been provided, and the bondingelectrodes 19 of the semiconductor chip 16 and the pads 14 areelectrically connected. In the embodiment shown in the diagrams, sincethe semiconductor chip 16 is mounted with its face down, the solder SD1or the bumps shown in FIG. 16 are used as the connecting means.

[0131] Herein, there is a great significance in having the surface ofthe heat radiation electrode 15 protrude beyond the surfaces of the pads14 by the distance “d”.

[0132] An Au bump comprises at least one stage of an Au cluster, so thatthe thickness of which would be 40 μm for one stage, and 70 to 80 μm fortwo stages. Accordingly, by having the surface of the heat radiationelectrode 15 protrude beyond the surfaces of the pads 14 by thesubstantial thickness of the bumps, the gap “d” may be reduced.

[0133] In the case of solder bumps or solder balls, the thickness wouldbe approximately 50 to 70 μm, and the gap may be reduced based on thesame principle. Since a brazing material such as solder has a goodwettability with the pads, it spreads out on the surfaces of the padswhen it is in a molten state, thereby reducing its thickness. However,since the spacing between the bonding electrodes and the pads isdetermined by the amount of protrusion of the heat radiation electrode,the thickness of the brazing material would be determined by this amountof protrusion, so that spreading-out of solder is also restrained.Accordingly, by the extent the thickness of the brazing material can beincreased, the stress applied to the solder may be more distributed,thereby suppressing the deterioration caused by heat cycles.

[0134] In this bonding process, since the pads 14 are integral with theconductive foil 40, and the back surface of the conductive foil 40 isflat, the device can be abutted to the table of the bonding machine bythe plane. Accordingly, if the conductive foil 40 is perfectly fixedonto the bonding table, the pads 14 and the solder balls formed on thesemiconductor chip 16 are all abutted in place, so that solderingfailures would not occur. The fixation to the bonding table may beachieved by, for example, providing a plurality of vacuum holes over theentire surface of the table. There are other alternative methods forproviding these connections, which will be explained at the end of thissection with reference to FIG. 16.

[0135] The semiconductor chip may be mounted without using a supportingsubstrate, and the solder balls are used instead of metal thin lines, sothat the semiconductor chip 16 may be disposed at a position lower bythat extent. Accordingly, the outer thickness of the package may bereduced as later explained.

[0136] Where an under fill is used as the insulating adhesive means 17,the under fill is introduced after the semiconductor chip 16 and thepads 14 are attached. (FIG. 6)

[0137] The insulating resin 13 is then formed over the entire regionincluding the semiconductor chip 16. For the insulating resin, either athermoplastic resin or a heat-curable resin may be used.

[0138] It may be formed via transfer molding, injection molding, dippingor coating. For a heat-curable resin such as epoxy resin, transfermolding may be employed, and for a thermoplastic resin such as liquidcrystal polymer or polyphenylene sulfide etc., injection molding may beemployed.

[0139] In the present embodiment, the thickness of the insulating resinis adjusted so that its top end comes at approximately 100 μm from theback surface of the semiconductor chip 16. This thickness may be madelarger or smaller depending on the desired strength of the semiconductordevice. Alternatively, the back surface of the semiconductor chip maybeexposed. In this case, radiator fins may be attached thereon, or directexternal dissipation of the heat generated by the semiconductor chip maybe attempted.

[0140] Since the pads 14, wirings 30, the external connection electrodes31 and the heat radiation electrode 15 are all integral with theconductive foil 40 that is in a form of a sheet, these copper foilpatterns would never be displaced during the resin injection step aslong as the conductive foil 40 itself is not displaced. In addition,unlike lead frames, these conductive patterns would never generateflashes of the resin.

[0141] As explained in the above, within the insulating resin 13, thepads 14, wirings 30, external connection electrodes 31 and the heatradiation electrode 15 that are formed as convex features are embeddedalong with the semiconductor chip 16, and the portion of the conductivefoil 40 below its convex features is exposed from the back surface.(FIG. 7)

[0142] Thereafter, the portion of the conductive foil 40 exposed on theback surface of the insulating resin 13 is eliminated, therebyseparating the pads 14, wirings 30, external electrodes 31 and heatradiation electrode 15 into individual elements.

[0143] For this separation step, various approaches may be contemplated.For example, they may be separated by etching the back surface, or bypolishing or grinding, or even by the combination thereof. For example,where the grinding is performed until the insulating resin 13 isexposed, there is a risk of having residues or stretched metal particlesfrom the ground conductive foil 40 encroach into the insulating resin 13or the insulating adhesive means 17. Accordingly, by using an etchingapproach, the separation may be achieved without having the metalresidues from the conductive foil 40 encroach into the surface of theinsulating resin 13 or the insulating adhesive means 17 located betweenthe Cu patterns. In this way, short-circuiting between the patternsarranged at fine intervals may be prevented.

[0144] In a case where a plurality of units, each comprising a singlesemiconductor device 10B, are integrally formed, a dicing step isadditionally performed after this separation step.

[0145] Although a dicing apparatus is used herein to individuallyseparate the units, it is also possible to perform this step bychocolate-bar-breaking, pressing or cutting.

[0146] According to this embodiment, after separating the Cu patterns,an insulating film 26 is formed over the patterns 14, 30, 31 and 15, andthe insulating film 26 is then patterned so as to expose the portionsindicated by the dotted circles shown in FIG. 3A. Thereafter, it isdiced at the sections indicated by arrows into individual semiconductordevices 10B.

[0147] The solder balls 42 may be formed either before or after thedicing step.

[0148] According to the manufacturing method above, a thin and smallpackage with a superior heat dissipation capability is fabricated, inwhich the bonding pads, wirings, external connection electrodes, heatradiation electrode and semiconductor chip are embedded within theinsulating resin.

[0149] As shown in FIG. 9, the molding may alternatively be achieved byusing the insulating adhesive means 17, without using the insulatingresin 13. The patterns PTN shown in FIG. 10 represent the pads, wirings,external connection electrodes, and the hatched regions shown thereonrepresent formation patterns of the film for preventing solder running.This film serves to prevent solder running, and at the same time, it isapplied to the other regions to improve the adhesion of the insulatingadhesive means. As for alternatives, patterns A through E areillustrated, however, any other pattern may be selected. Thesolder-running prevention film may also be formed over the entire regionother than the regions for solder connections.

[0150] The effects obtained by the above manufacturing method will nowbe explained.

[0151] First, since the conductive patterns are half-etched andsupported integrally with the conductive foil, a substrate that hasconventionally been employed for supporting is unnecessitated.

[0152] Second, since the convex conductive patterns are formed byhalf-etching the conductive foil, it is possible to form finerconductive patterns. Accordingly, their widths and intervals may beminimized, allowing the formation of a package having a smallertwo-dimensional size.

[0153] Third, since the device may be constituted by conductivepatterns, a semiconductor chip, connection means and a molding material,the structure would include only the elements that are truly essential,eliminating the excessive use of materials, thus, a thin and smallsemiconductor device may be realized with a substantially reduced cost.

[0154] Fourth, since the pads, wirings, external connection electrodesand heat radiation electrode are formed as convex portions throughhalf-etching, and the separation to individual elements is performedafter the molding step, tie-bars and suspension leads would not benecessary. Accordingly, the necessity for the formation of tie-bars(suspension leads), and cutting step of the tie-bars (suspension leads)are completely eliminated in the present invention.

[0155] Fifth, since the conductive foil is eliminated from the backsurface of the insulating resin to separate the conductive patternsafter the convex conductive patterns are embedded within the insulatingresin, flashes of the resin formed between leads as those present in theconventional lead frames can be eliminated.

[0156] Sixth, since the semiconductor chip is affixed with the heatradiation electrode via the insulating adhesive means, and thehead-dissipating electrode is exposed from the back surface, the heatgenerated by the semiconductor device can be dissipated efficiently fromthe surface of the semiconductor device to the heat radiation electrode.Furthermore, by mixing fillers such as those made of silicon oxide oraluminum oxide into the insulating adhesive means, the heat-dissipatingcapability thereof may further be improved. By uniformly designing thefiller size, the spacing between the semiconductor chip 16 and theconductive patterns may be evenly retained.

[0157] (Embodiment 5)

[0158] The fifth embodiment is provided for illustrating a semiconductordevice 10A, 10B to which a metal plate 23 is affixed and a semiconductormodule using the same. FIG. 1 shows this type of semiconductor module(FCA) 50. The semiconductor device mounted thereto is the semiconductordevice 10B shown in FIG. 3.

[0159] First, a first supporting member 11 constituted by a flexiblesheet will be explained. In the present embodiment, it comprises a firstPI sheet 51, a first adhesion layer 52, a conductive pattern 53, asecond adhesion layer 54 and a second PI sheet 55 that are sequentiallylaminated from the bottom. When forming the conductive pattern inmultiple layers, additional adhesion layers may be used, and upper andlower layers of the conductive pattern may be electrically connectedthrough contact holes. Provided in this first supporting member 11 is afirst opening 12 which would allow at least a metal plate 23 to beexposed as shown in FIG. 1C.

[0160] A second opening 56 is also formed in order to expose theconductive pattern. The second opening 56 may entirely expose thecorresponding conductive pattern 32, or may partially expose only theportion for forming connections. For example, the second PI sheet 55 andthe second adhesion layer 54 may entirely be eliminated, or, as shown inthe figure, while entirely eliminating the second PI sheet, the secondadhesion layer 54 may partially be eliminated only at the locationsrequired to be exposed. According to the later manner, running of thesolder 27 may be prevented.

[0161] The significance of this semiconductor device of the presentinvention is in that a metal plate 23 is adhered to the back surface ofthe heat radiation electrode 15. The significance of the semiconductormodule of the present invention is in that the metal plate 23 and theback surface of the first supporting member would become substantiallywithin the same plane.

[0162] The thickness of the metal plate 23 is determined according tothe thicknesses of the first supporting member 11 and the fixation plate25. The thicknesses are respectively determined in a manner so that themetal plate 23 exposed from the first opening 12 and the back surface ofthe first supporting member 11 can be substantially within a same planewhen the pads 14 and the conductive pattern 32 are affixed togetherthrough the solder balls 27. Accordingly, the metal plate 23 maybeabutted to the second supporting member or abutted and adhered to thefixation plate 25 provided on the second supporting member.

[0163] Several examples of this connection structure are given below.

[0164] In the first example of the structure, a light-weight metal platesuch as the one made of Al or stainless steel etc., or a ceramicsubstrate is used as the second supporting member 24, and the metalplate 23 which has been affixed on the back surface of the semiconductordevice 10 is abutted thereto. That is, in this structure, the abutmentto the second supporting member 24 is provided without the use of thefixation plate 25. The fixation between the heat radiation electrode 15and the metal plate 23, and between the metal plate 23 and the secondsupporting member 24 is achieved by a brazing material such as solderetc. or an insulating adhesive means containing fillers having asuperior thermal conductivity.

[0165] In the second example, the structure employs a light-weight metalplate such as the one made of Al or stainless steel etc. or a ceramicsubstrate as for the second supporting member 24, and a fixation plate25 is formed thereon, and this fixation plate 25 and the metal plate 23is affixed together.

[0166] Where an Al plate is used as the second supporting member 24 forexample, the fixation plate 25 is preferably the one made of Cu. This isbecause Cu can be plated over Al. This may be formed in a thickness of,up to about 10 μm. In addition, since it is a plated film, it may beformed in intimate contact with the second supporting member 24, makingthe thermal resistance between the fixation plate 25 and the secondsupporting member 24 extremely small. Alternatively, a conductive pastmay be applied to form the fixation plate 25.

[0167] The Cu fixation plate 25 and the Al substrate may instead beadhered using an adhesive, however, in this case the thermal resistancewould become larger.

[0168] Where a ceramic substrate is used as the second supporting member24, the fixation plate 25 is formed on an electrode formed byprint-baking a conductive paste.

[0169] The second supporting member 24 and the first supporting member11 are adhered together via a third adhesion layer 57.

[0170] For instance;

[0171] First PI sheet 51: 25 μm

[0172] Second PI sheet 55: 25 μm

[0173] First through third adhesion layers 52, 54, 57: 25 μm after beingbaked (an acrylic adhesive is used)

[0174] Solder balls 27: 50 μm;

[0175] Conductive pattern 53: 25 μm

[0176] Fixation plate 25: approximately 25 μm.

[0177] Where the thicknesses of the respective films are adjusted inthis way, then after affixing the semiconductor device onto the firstsupporting member 11, the second supporting member 24 having thefixation plated 25 formed thereon would be readily adhered.

[0178] Where a module is provided, in which the second supporting member24 is attached to the first supporting member 11, and the semiconductordevice 10 is placed within an opening 56 provided in this module andthen soldered, the soldering may be performed at once without promotingconnection failures.

[0179] Accordingly, the heat generated by the semiconductor chip 16 maybe dissipated into the second supporting member 24 via theheat-dissipating plate 15, metal plate 23 and fixation plate. Moreover,since it provides a substantial reduction in the thermal resistancecompared to that of the conventional art structure (FIG. 18B), thedriving current and the driving frequency of the semiconductor chip 16can be maximized. The back surface of this second supporting member 24may be attached to the actuator 107, bottom of the casing 101 or the arm105 shown in FIG. 17. Therefore, the heat from the semiconductor chipcan ultimately be emitted to the outside via the casing 101.Accordingly, even if the semiconductor module is mounted within the harddisk 100, the temperature of the semiconductor chip itself is keptrelatively low, so that the read/write speed of the hard disk 100 can befurther accelerated. This FCA may be mounted on an apparatus other thana hard disk. In this case, the second supporting member should beabutted to a member of the apparatus having a small thermal resistance.Where it is mounted in any other apparatus, a printed board or a ceramicsubstrate may also be used instead of the flexible sheet.

[0180] (Embodiment 6)

[0181] The sixth embodiment is provided to illustrate a semiconductordevice 10C in which the heat radiation electrode 15 is made protrusiveto substitute the metal plate, and a semiconductor module 50A using thesame. FIG. 11 shows a structure in which the heat radiation electrode15A protrudes beyond the top surfaces and the back surfaces of the pads14 as if the heat radiation electrode 15 and the metal plate 23 areconstituted by an integral element.

[0182] First, the manufacturing method thereof will be explained withreference to FIGS. 12 through 14. Its manufacturing steps correspondingto the steps illustrated in FIGS. 4 through 8 are identical and thedescriptions for these steps would not be repeated.

[0183]FIG. 12 is showing the conductive foil 40 being covered by theinsulating resin 13, and on the portion corresponding to the heatradiation electrode 15, a photo resist PR is formed. When thisconductive foil 40 is etched via the photo resist PR, the resultant heatradiation electrode 15A would have a structure which protrudes beyondthe back surfaces of the pads 14. Alternatively, a conductive film madeof Ag or Au etc. may be selectively formed and used as a mask instead ofthe photo resist PR. This film would function also as an anti-oxidizingfilm.

[0184] In the structure such as the one shown in FIG. 1 in which themetal plate 23 is adhered, since the metal plate 23 is extremely thin(i.e. 125 μm), the workability is extremely poor. On the other hand,where the heat radiation electrode 15A is etched to have the protrusivestructure, the attaching step of the metal plate 23 may be eliminated.

[0185] Next, as shown in FIG. 14, after the pads 14, wirings 30 andexternal connection electrodes 31 are completely separated, theinsulating film 26 is formed, and the portions for providing solderballs are exposed. After it is affixed via the solder balls 42, it isdiced at the sections indicated by arrows.

[0186] The isolated semiconductor device is then mounted on the firstsupporting member 11 as shown in FIG. 11. Thereafter, the secondsupporting member 24 is attached thereto as previously mentioned. Atthis point, since the heat radiation electrode 15A is protrusive, it canbe readily connected to the fixation plate 25 via soldering etc.

[0187] Shown in FIG. 14B is a structure in which the back surface of thesemiconductor chip 16 is exposed from the insulating resin. For example,by performing the molding step while abutting the back surface of thesemiconductor chip to the top mold, then the molded structure such asthe one shown may be obtained.

[0188] (Embodiment 7)

[0189] The seventh embodiment is provided to illustrate anothersemiconductor device. FIG. 15A shows a plan view of the semiconductordevice according to the present invention, and FIG. 15B shows across-sectional view of FIG. 15A taken along the line A-A.

[0190] According to the present invention, a first heat radiationelectrode 70A and a second heat radiation electrode 70B are disposedsubstantially in a same plane, and along the peripheries thereof, pads14 are arranged. The back surfaces of these pads 14 themselves serve asthe external connection electrodes, however, the re-arranged type ofwirings shown in FIG. 3 may instead be employed. Between the chips, atleast one bridge 71 is disposed. At the both ends of the bridges 71,pads 14 are integrally formed, and these pads 14 too are connected tothe bonding electrodes 19.

[0191] Over the first heat radiation electrode 70A which protrudesupwardly, a first semiconductor chip 16A is affixed, and over the secondheat radiation electrode 70B which similarly protrudes upwardly, asecond semiconductor chip 16B is affixed, and they are connected viasolder.

[0192] As apparent from the above explanation, by half-etching theconductive foil, and performing the molding of the insulating resin 13before the foil is completely separated, the risk of having the bridges71 fall down or slip out may be eliminated.

[0193] As in the present embodiment, a plurality of chips may bepackaged into a single package.

[0194] The embodiments described heretofore are provided in order toillustrate the structures designed in consideration with theheat-dissipating capability of a single read/write amplifying IC.However, where the applications to various types of apparatus arecontemplated, there may be a case in which the heat-dissipatingcapability of a plurality of semiconductor chips must be considered. Ofcourse, it is possible to package them into separate, individualpackages, however, the plurality of the semiconductor chips may also bepackaged into one package as illustrated in FIG. 15.

[0195] The metal plates may of course be provided in either thestructure in which they are attached to the heat radiation electrodes asshown in FIG. 1 or the structure in which the heat radiation electrodesthemselves are designed to have the protrusive structure as shown inFIG. 11. These devices may be mounted on a flexible sheet or a flexiblesheet having the second supporting member attached thereon.

[0196]FIG. 16 shows a series of diagrams for illustrating severalmethods that are applicable to any of the embodiments for providingconnection between bumps B formed on the semiconductor chip 16 and thepads 14. P represents a plated film made of Au, Ag or the like formed ifnecessary.

[0197]FIG. 16A illustrates an ACP (anisotropic conductive paste/film)method in which the electrical conduction is achieved by providingconductive particles between the bump B and the pad 14 (or plated filmP), and applying pressure.

[0198]FIG. 16B illustrates an SBB (stand bump bonding) method in which,as the bump B and the pad 14 (or plated film) are connected, conductivepaste CP is simultaneously provided at the periphery.

[0199]FIG. 16C illustrates an ESC (epoxy encapsulated solder connection)method in which, as the bump B is pressure-welded, molten solder SD issimultaneously provided at the periphery.

[0200]FIG. 16D illustrates an NCP (non-conductive paste) method in whichan insulating adhesive means is provided around the bump B which hasbeen pressure-welded to achieve electrical conduction.

[0201]FIG. 16E illustrates a GGI (gold-gold interconnection) method inwhich an Au bump and a plated Au film P are connected by ultrasonicwave.

[0202]FIG. 16F illustrates a solder bump method in which the connectionis achieved through soldering, and an insulating adhesive means or anunder fill is introduced into the gap. The disclosure herein employsthis method.

[0203] The embodiments described above are explained with a flexiblesheet as a substrate, however, a ceramic substrate, a printed board, aflexible sheet, a metal substrate or a glass substrate etc. can also beapplied to the substrate of the present invention.

[0204] As listed above, there are a variety of connecting methodsavailable, however, in consideration with the connection strength, amethod should be selected from the above. A structure such as the onefrom the above may also be used for the connections between the backsurfaces of the external connection electrodes and the first supportingmember 11.

[0205] As apparent from the above description, according to the presentinvention, the distance between the semiconductor chip and the heatradiation electrode may be made smaller by having the surface of theheat radiation electrode protrude beyond the surfaces of the pads.Especially, the distance between the bonding electrodes and the pads isdetermined by the protruding amount of the heat radiation electrode, sothat the thickness of the brazing material is determined by thisprotruding amount. Accordingly, by the amount the thickness of thebrazing material can be increased, the stress applied to the solder canbe more distributed, thereby enabling to suppress the deterioration byheat cycles.

[0206] The present invention also provides an advantage in that themounting of the device on an FCA can be facilitated by providing thesemiconductor device in which the metal plate protrudes beyond the backsurfaces of the external connection electrodes or the pads by affixing ametal plate to a heat radiation electrode exposed from the back surfaceof the package.

[0207] Especially, by providing an opening to the FCA so as to allow theback surface of the FCA and the heat radiation electrode of thesemiconductor device to be within a same plane, the abutment to thesecond supporting member can be readily achieved.

[0208] By using Al as for the second supporting member material and byforming thereon a fixation plate made of Cu, and affixing the heatradiation electrode or the metal plate to this fixation plate, the heatgenerated by the semiconductor chip may be externally dissipated via thesecond supporting member.

[0209] Accordingly, the temperature rise of the semiconductor chip maybe prevented, allowing the device to operate at a higher performancelevel close to its inherent capability. Especially, such an FCA used ina hard disk is capable of providing efficient external emission of heatso that the read/write speed of the hard disk may be increased.

1. to
 34. canceled.
 35. A hard disk comprising a semiconductor device,wherein the semiconductor device including: a semiconductor chipintegrally molded by an insulating resin in a face-down state; a padelectrically connected to a bonding electrode of the semiconductor chipand provided to expose from the insulating resin; a heat radiationelectrode disposed on the surface of the semiconductor chip and providedto expose from the insulating resin; and a connecting means whichconnects the bonding electrode and the pad, wherein the top surface ofthe heat radiation electrode protrudes beyond the top surface of thepad, and by the amount of the protrusion, the thickness of theconnecting means is practically determined.
 36. A hard disk comprising asemiconductor module, wherein the semiconductor module including: afirst supporting member provided a conductive pattern; a semiconductordevice including: a semiconductor chip electrically connected to theconductive pattern and integrally molded by an insulating resin in aface-down state; a pad electrically connected to a bonding electrode ofthe semiconductor chip and the conductive pattern, and provided toexpose from the insulating resin; a heat radiation electrode disposed onthe surface of the semiconductor chip and provided to expose from theinsulating resin; a connecting means which connects the bondingelectrode and the pad; an opening portion provided in the firstsupporting member at a location corresponding to the heat radiationelectrode; and a metal plate affixed to the heat radiation electrode inthe opening portion, wherein the top surface of the heat radiationelectrode protrudes beyond the top surface of the pad, and by the amountof this protrusion, the thickness of the connecting means is practicallydetermined.
 37. A hard disk comprising a semiconductor device, whereinthe semiconductor device including: a semiconductor chip integrallymolded by an insulating resin in a face-down state; a pad electricallyconnected to a bonding electrode of the semiconductor chip; an externalconnection electrode extending via a wiring integral to the pad andprovided to expose from the insulating resin; a heat radiation electrodedisposed on the surface of the semiconductor chip; and a connectingmeans which connects the bonding electrode and the pad, wherein the topsurface of the heat radiation electrode protrudes beyond the top surfaceof the pad, and by the amount of this protrusion, the thickness of theconnecting means is practically determined.
 38. A hard disk comprising asemiconductor module, wherein the semiconductor module including: afirst supporting member having a conductive pattern; a semiconductordevice including: a semiconductor chip electrically connected to theconductive pattern and integrally molded by an insulating resin in aface-down state; a pad electrically connected to a bonding electrode ofthe semiconductor chip; an external connection electrode provided via awiring integral to the pad and the conductive pattern, and provided toexpose from the insulating resin; a heat radiation electrode disposed onthe surface of the semiconductor chip and provided to expose from theinsulating resin; a connecting means which connects the bondingelectrode and the pad; an opening portion provided in the firstsupporting member at a location corresponding to the heat radiationelectrode; and a metal plate affixed to the heat radiation electrode inthe opening portion, wherein the top surface of the heat radiationelectrode protrudes beyond the top surface of the pad, and by the amountof this protrusion, the thickness of the connecting means is practicallydetermined.